Torque wrenches



Oct. 1, 1968 A. AGOSTINI TORQUE WRENCHES Filed June 24, 1966 7 United States Patent 3,403,551 TORQUE WRENCHES Antoine Agostini, Maisons-Lafiitte, France, assignor to Societe Anonyme Societe des Automobiles Simca, Paris, France Filed June 24, 1966, Ser. No. 560,236 Claims priority, application France, June 28, 1965,

4 Claims. (1173-139) ABSTRACT OF THE DISCLOSURE A torque wrench comprising an outer sleeve having a substantially transversely extending handle rigidly secured thereto, an inner sleeve mounted within the outer sleeve and having slots between its two ends to define a plurality of deformable blades. One end of the inner sleeve is mounted for rotation with the outer sleeve, and the other end of the inner sleeve is rigid with a threaded member adapted to receive a tool head for cooperation with an element to which the wrench is to be applied. A member for measuring the displacement of the heads of the inner sleeve, under the action of torque transmitted by the wrench from the handle to the element, is mounted at one end of the inner sleeve.

The present invention relates generally to torque wrenches.

Conventional torque wrenches most often have the disadvantage of being fairly expensive and, in particular, fairly inaccurate, thus presenting serious disadvantages when the torque load of components to be tightened, such as screws, bolts, etc. must be between two fairly close and well determined values.

A torque wrench according to the invention may be used either for ascertaining the torque which has already been applied during a tightening operation which has already been effected, or for carrying out a tightening operation, under the normal conditions of use of a torque wrench.

Other characteristics and advantages of the present invention will appear from the following description of an embodiment given solely by way of example, said description being made with reference to the accompanying drawing, in which the single figure is a longitudinal section of a torque wrench according to the invention.

Referring now to the drawing, a torque wrench according to the invention comprises a handle 1, for holding and controlling the wrench, this handle being welded, or fixed in any other desired manner, to an outer sleeve 2. An inner sleeve 3 whose diameter, along part of its length, is smaller than the internal diameter of the sleeve 2, is arranged in the latter and is located by one end by a tip 4, which is, for example, square or hexagonal, interlocking in the corresponding end of the sleeve 2. Two bearings 5 and 6, whose function will be described later, are provided between the sleeves 2 and 3.

A screw tip 7 formed either integrally with the lower end 22 of the sleeve 3, or secured in any desired manner thereto, is capable of receiving an intermediate component of conventional type such as a socket 19, a bearing or a tip which is arranged between the tip 7 and the mechanical component to be tightened or controlled such as a bolt 20.

The sleeve 3 is tubular in shape in its median part between its two ends 21, 22 and has slots 8 which, in the example shown in the drawing, are inclined with respect to the longitudinal axis of the tubular part of the sleeve and form a predetermined angle therewith, said slots 8 being parallel so as to define deformable blades 81:. The

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slots 8 could also be parallel to the longitudinal axis of the inner sleeve 3. The slots 8 shown in the drawing have rounded ends, but this is not of course essential and the slots may be of any desired shape.

In addition, the upper end 21 of the sleeve 3 has a threaded recess 9 in which is screwed a dial indicator 10, having a rod 11 which extends into the internal cavity of the sleeve 3. The dial indicator 10 is of conventional type having an indicating needle 18 and therefore does not need to be described in greater detail. The lower end 12 of the rod 11 is urged by a spring (not shown) arranged in the casing of the dial indicator 10, against the upper face of the head 16 of a screw 13, screwed into an internally threaded aperture 14 of the nosepiece 22 (i.e., the toothed end) of the sleeve 3, the degree of penetration of the screw 13 being regulatable by shims 15 arranged between the head 16 of the screw 13 and the surface 17 of the sleeve 3.

The principle of operation of the torque Wrench described above is as follows:

Let us assume that by means of the handle 1 and by means of the tip 7, a torque is applied to an element such as the bolt 20. The resistance exerted on the tip 7 will produce a torsion on the sleeve 3 since the latter is rigidly secured in the outer sleeve 2 by its upper part or tip 4. The torsion of the sleeve 3 is rendered possible by the existence of the slots 8, and the concentricity as well as the relative displacement of the sleeves 2 and 3 are respectively maintained and facilitated by the presence of the bearings 5 and 6, fitting in the sleeve 2. If the slots -8 are parallel, the torsion of the sleeve 3 is shown, whatever may be the direction of application of the torque, by a deformation of the blades 8a and a shortening of this sleeve, in other words, the head 16 of the screw 13 integral with the lower part 22 of the sleeve, will approach the upper end 21 of the sleeve 3, consequently exerting a pressure on the rod 12 of the dial indicator. In such a wrench, the dial of the indicator 10 will advantageously be calibrated in increasing values, from one end of its scale to the other. If on the contrary the slots 8 are sloping, the torsion of the sleeve 3 in one direction will produce a shortening, the head 16 then approaching the upper end 21 of the sleeve 3 and exerting a pressure on the rod 12 and, in contradistinction, if the torsion of the sleeve 3 is produced in the other direction, the sleeve 3 will be elongated; the head 16 will become separated from the upper end 21 of the sleeve 3, followed by the point of the dial indicator urged by its spring. If it were desired to utilize the wrench in the two directions, it would then be advantageous, with sloping slots -8, to locate the zero of the scale at the center, this. zero being the initial point of two parts of the scale, one directed towards the left of the figure and the other towards the right, in the increasing values.

A wrench according to the invention is extremely simple, robust, light in Weight, accurate and easily operable.

The measurement of the displacement which is ensured in the example chosen, by a dial indicator of conventional type, may be effected by any other mechanical, hydraulic, pneumatic or electrical indicating means.

It will be understood that the present invention is not limited to the specific arrangement described and shown in the drawing and that various modifications may be made thereto without departing from its scope as defined by the appended claims.

I claim:

1. A torque wrench for transmitting torque to an element comprising an outer sleeve having a substantially transversely extending handle rigidly secured thereto, an inner sleeve having two ends mounted within said outer sleeve, said inner sleeve being slotted to define a plurality of deformable blades between its two ends, one end of the inner sleeve being mounted for rotation with the outer sleeve, a threaded member rigid with the other end of the inner sleeve, a tool head removably mounted on said threaded member for cooperation with said element to which the wrench is to be applied, and indicator means carried at the one end of the inner sleeve, said indicator means including a movable rod depending thereform and bearing against said other end of the inner sleeve so as to be capable of measuring the relative displacement of the ends of the inner sleeve under the action of torque transmitted from the handle to the element.

2. The torque wrench of claim 1, wherein said inner sleeve includes an internally threaded aperture at said other end, a screw having a head and threadably engaging in said aperture, and adjusting shims displaceably mounted between the inner sleeve and said screw head, said screw head being in contact with the rod of the indicator means.

3. A torque wrench according to claim 1, wherein said a r 4 slots in the wall of said inner sleeve are arranged with their axes parallel.

4. A torque wrench according to claim 1, wherein said slots in the wall of said inner sleeve are disposed with their axes parallel and inclined by a determined angle with respect to the longitudinal axis of the tubular part of said inner sleeve.

' References Cited UNITED STATES PATENTS 2,210,632 10/1940 Naden 73139 2,260,036 10/1941 Kuehni 73-136 3,009,360 11/ 1961 Morsewich 267-1 XR 3,080,334 5/1963 Dean 73139 3,153,930 10/1964 Jackson 73134 RICHARD C. QUEISSER, Primary Examiner.

C. A. RUEHL, Assistant Examiner. 

